U.S. patent application number 14/809373 was filed with the patent office on 2016-02-04 for substrate cleaning method and recording medium.
The applicant listed for this patent is JSR CORPORATION, TOKYO ELECTRON LIMITED. Invention is credited to Meitoku AIBARA, Itaru KANNO, Hisashi KAWANO, Kenji MOCHIDA, Motoyuki SHIMA, Masami YAMASHITA, Yuki YOSHIDA.
Application Number | 20160035564 14/809373 |
Document ID | / |
Family ID | 55180773 |
Filed Date | 2016-02-04 |
United States Patent
Application |
20160035564 |
Kind Code |
A1 |
AIBARA; Meitoku ; et
al. |
February 4, 2016 |
SUBSTRATE CLEANING METHOD AND RECORDING MEDIUM
Abstract
An object of the present invention is to be able to obtain a
high removing performance of particles. The substrate processing
method according to the exemplary embodiment comprises a
film-forming treatment solution supply step and a removing solution
supply step. The film-forming treatment solution supply step
comprising supplying to a substrate, a film-forming treatment
solution containing an organic solvent and a fluorine-containing
polymer that is soluble in the organic solvent is supplied. The
removing solution supply step comprises supplying to a treatment
film formed by solidification or curing of the film-forming
treatment solution on the substrate, a removing solution capable of
removing the treatment film.
Inventors: |
AIBARA; Meitoku; (Koshi-Shi,
JP) ; YOSHIDA; Yuki; (Koshi-Shi, JP) ; KAWANO;
Hisashi; (Koshi-Shi, JP) ; YAMASHITA; Masami;
(Koshi-Shi, JP) ; KANNO; Itaru; (Tokyo, JP)
; MOCHIDA; Kenji; (Tokyo, JP) ; SHIMA;
Motoyuki; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOKYO ELECTRON LIMITED
JSR CORPORATION |
Tokyo
Tokyo |
|
JP
JP |
|
|
Family ID: |
55180773 |
Appl. No.: |
14/809373 |
Filed: |
July 27, 2015 |
Current U.S.
Class: |
134/4 |
Current CPC
Class: |
H01L 21/02057 20130101;
B08B 3/08 20130101; H01L 21/67051 20130101; H01L 21/67028 20130101;
H01L 21/6715 20130101; H01L 21/02041 20130101 |
International
Class: |
H01L 21/02 20060101
H01L021/02; B08B 3/08 20060101 B08B003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2014 |
JP |
2014-157194 |
Claims
1. A substrate cleaning method comprising: a film-forming treatment
solution supply step of supplying to a substrate, a film-forming
treatment solution comprising an organic solvent and a
fluorine-containing polymer that is soluble in the organic solvent;
and a removing solution supply step of supplying to a treatment
film formed by solidification or curing of the film-forming
treatment solution on the substrate, a removing solution capable of
removing the treatment film.
2. The substrate cleaning method according to claim 1, wherein the
polymer has a partial structure represented by the following
formula (1): ##STR00008## wherein R.sup.1 and R.sup.2 each
independently represents a hydrogen atom, a fluorine atom, an alkyl
group having 1 to 8 carbon atoms, or a fluorinated alkyl group
having 1 to 8 carbon atoms, provided that at least one of R.sup.1
and R.sup.2 is a fluorine atom or a fluorinated alkyl group having
1 to 8 carbon atoms; and the symbol * shows a bonding site with
another atom constituting the polymer.
3. The substrate cleaning method according to claim 2, wherein the
film-forming treatment solution further contains a low-molecular
organic acid.
4. The substrate cleaning method according to claim 3, wherein the
low-molecular organic acid is a polycarboxylic acid.
5. The substrate cleaning method according to claim 2, wherein the
film-forming treatment solution contains water at an amount of 20%
or less by mass relative to total mass of the organic solvent and
the water.
6. The substrate cleaning method according to claim 1, wherein the
removing solution supply step comprises: a stripping treatment
solution supply step of supplying to the treatment film, a
stripping treatment solution capable of stripping the treatment
film from the substrate; and a dissolving treatment solution supply
step of, after the stripping treatment solution supply step,
supplying to the treatment film, a dissolving treatment solution
capable of dissolving the treatment film.
7. The substrate cleaning method according to claim 6, wherein the
stripping treatment solution is pure water.
8. A non-transitory computer-readable recording medium storing a
program that is executable by a computer and controls a substrate
cleaning system, wherein upon execution of the program, the
computer controls the substrate cleaning system so that the
substrate cleaning method according to claim 1 is performed.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2014-157194 filed on
Jul. 31, 2014; the entire contents of which are incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Exemplary embodiments of the present disclosure relate to a
substrate cleaning method and a recording medium.
[0004] 2. Background Art
[0005] From the past, a substrate cleaning device has been known
with which particles attached to a substrate such as a silicon
wafer and a compound semiconductor wafer are removed. For example,
in Japanese Patent Laid-Open Publication No. 2014-123704, a
substrate cleaning method is disclosed wherein a treatment film is
formed on surface of a substrate by using a topcoat solution, and
then by removing this treatment film, particles on the substrate
are removed together with the treatment film.
SUMMARY OF THE INVENTION
[0006] However, by the method described in Japanese Patent
Laid-Open Publication No. 2014-123704, for example, when a
substrate having a underlayer film is processed, the treatment film
cannot be fully removed depending on the substrate to be treated,
so that there have been a possibility that a high removing
performance of the particles cannot be obtained.
[0007] An exemplary embodiment has an object to provide a substrate
cleaning method and a recording medium, with which a high removing
performance of the particles can be obtained.
[0008] A substrate cleaning method according to the exemplary
embodiment comprises a film-forming treatment solution supply step
and a removing solution supply step. The film-forming treatment
solution supply step comprises supplying to a substrate, a
film-forming treatment solution containing an organic solvent and a
fluorine-containing polymer that is soluble in the organic solvent.
The removing solution supply step comprises supplying to a
treatment film formed by solidification or curing of the
film-forming treatment solution on the substrate, a removing
solution capable of removing the treatment film.
[0009] According to the exemplary embodiment, a high removing
performance of the particles can be obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1A is an explanatory drawing of the substrate cleaning
method according to the exemplary embodiment of the present
disclosure.
[0011] FIG. 1B is an explanatory drawing of the substrate cleaning
method according to the exemplary embodiment of the present
disclosure.
[0012] FIG. 1C is an explanatory drawing of the substrate cleaning
method according to the exemplary embodiment of the present
disclosure.
[0013] FIG. 1D is an explanatory drawing of the substrate cleaning
method according to the exemplary embodiment of the present
disclosure.
[0014] FIG. 1E is an explanatory drawing of the substrate cleaning
method according to the exemplary embodiment of the present
disclosure.
[0015] FIG. 2 shows evaluation results with regard to the
removabilities of a conventional topcoat solution and of the
film-forming treatment solution from the substrate according to the
exemplary embodiment of the present disclosure.
[0016] FIG. 3 is a schematic diagram illustrating a structure of
the substrate cleaning system according to the exemplary embodiment
of the present disclosure.
[0017] FIG. 4 is a schematic diagram illustrating a structure of
the substrate cleaning device according to the exemplary embodiment
of the present disclosure.
[0018] FIG. 5 is a flow chart showing a processing procedure of the
substrate cleaning process performed by the substrate cleaning
device according to the exemplary embodiment of the present
disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Hereunder, by referring to the attached drawings, exemplary
embodiments of the substrate cleaning method and the recoding
medium disclosed by the present application will be explained in
detail. Meanwhile, the present invention is not restricted by the
exemplary embodiments shown below.
[Substrate Cleaning Method]
[0020] First of all, contents of the substrate cleaning method
according to the exemplary embodiment of the present disclosure
will be explained by using FIG. 1A to FIG. 1E. FIG. 1A to FIG. 1E
are explanatory drawings of the substrate cleaning method according
to the exemplary embodiment of the present disclosure.
[0021] As shown in FIG. 1A, in the substrate cleaning method
according to the exemplary embodiment of the present disclosure, a
"film-forming treatment solution" is supplied to a pattern-formed
surface of a substrate such as a silicon wafer and a compound
semiconductor wafer (hereinafter, also referred to as "wafer
W").
[0022] The "film-forming treatment solution" of the exemplary
embodiment of the present disclosure is a composition for substrate
cleaning which comprises an organic solvent and a
fluorine-containing polymer that is soluble in the organic solvent
(preferably, a polymer having a partial structure represented by
the formula (1) discussed later). By using the film-forming
treatment solution, a high removing performance of particles can be
obtained regardless of the kind of the underlayer film. Meanwhile,
the polymer is not limited to the one having the partial structure
represented by the formula (1) discussed later, whereby if it
contains a fluorine atom, the same effect as mentioned above can be
obtained.
[0023] The film-forming treatment solution supplied to the
pattern-formed surface of the wafer W becomes a treatment film by
solidification or curing of the film-forming treatment solution.
This results in a state in which the pattern formed on the wafer W
and the particles P attached to the pattern are covered with the
treatment film (see FIG. 1B). Meanwhile, the term "solidification"
used herein means a solution becomes a solid; and the term "curing"
means that molecules are connected with one another to become a
polymer (for example, crosslinking and polymerization).
[0024] Next, as shown in FIG. 1B, a stripping treatment solution is
supplied to the treatment film formed on the wafer W. The stripping
treatment solution is a treatment solution for stripping the
treatment film from the wafer W.
[0025] After being supplied to the treatment film, the stripping
treatment solution penetrates into the treatment film to reach an
interface between the treatment film and the wafer W. Because the
stripping treatment solution penetrates to the interface between
the treatment film and the wafer W, the treatment film is stripped
in the state of "film" from the wafer W; and as a result, the
particles P attached to the pattern-formed surface are stripped
together with the treatment film from the wafer W (see FIG.
1C).
[0026] With this regard, for example, Japanese Patent Laid-Open
Publication No. 2014-123704 discloses a substrate cleaning method,
comprising forming a treatment film on a surface of a substrate by
using a topcoat solution, and then removing particles on the
substrate together with the treatment film by removing the
treatment film. The topcoat solution is a protective film applied
onto a surface of a resist film to inhibit penetration of an
immersion liquid into this resist film.
[0027] In the substrate cleaning method according to the exemplary
embodiment of the present disclosure, as the flow to remove the
treatment film, firstly the explanation was made about the
stripping of the treatment film formed on the substrate in the
state of film; however, if the topcoat solution mentioned above is
used, depending on the substrate having a underlayer film, such as
for example, SiN (silicon nitride) and TiN (titanium nitride),
sometimes the treatment film cannot be stripped fully, thereby
leading to the insufficient removability of the treatment film from
the substrate. In other words, depending on the substrate to be
processed, the treatment film cannot be fully removed, so that
there has been a possibility that the removing performance of the
particles cannot be fully expressed.
[0028] Therefore, in the substrate cleaning method according to the
exemplary embodiment of the present disclosure, the composition for
substrate cleaning mentioned before is used as the film-forming
treatment solution. The film-forming treatment solution as
mentioned above has a higher removability of the treatment film
from the substrate as compared with the conventional topcoat film;
and thus, a high removing performance of the particles can be
obtained even in the case that the substrate having a underlayer
film such as the SiN film and the TiN film is a target to be
processed.
[0029] Here, the evaluation results with regard to the
removabilities of the conventional topcoat solution and of the
film-forming treatment solution according to the exemplary
embodiment of the present disclosure from the substrate will be
explained by referring to FIG. 2. FIG. 2 shows the evaluation
results with regard to the removabilities of the conventional
topcoat solution and of the film-forming treatment solution
according to the exemplary embodiment of the present disclosure
from the substrate.
[0030] In FIG. 2, the study was done with regard to the case that
after each of the treatment film is formed with the topcoat
solution and with the film-forming treatment solution on a bare
silicon wafer and on a SiN wafer (a substrate having a SiN film),
DIW, i.e., pure water with a normal temperature (about 23 to 25
degrees) is supplied as the stripping treatment solution; and the
evaluation results of the removability of each of the treatment
films from the substrate are shown. In FIG. 2, "Good" means that
the removability of the treatment film from the substrate is 90% or
more, and "Poor" means that the removability of the same is 10% or
less.
[0031] As shown in FIG. 2, it can be seen that the treatment film
formed with the conventional topcoat solution can be stripped from
the substrate very well as far as the bare silicon wafer is a
target to be processed; however, when the SiN wafer is used as a
target to be processed, the treatment film cannot be sufficiently
stripped from the substrate, which indicates that the removability
thereof is deteriorated.
[0032] On the other hand, it can be seen that the treatment film of
the film-forming treatment solution according to the exemplary
embodiment of the present disclosure can be stripped very well from
the substrate in any of the cases that the bare silicon wafer and
the SiN wafer are targets to be processed so that a high
removability can be obtained.
[0033] As shown above, in the substrate cleaning method according
to the exemplary embodiment of the present disclosure, by using the
film-forming treatment solution, the removability against the
substrate having the underlayer film such as the SiN film can be
enhanced as compared with the conventional topcoat solution.
Therefore, according to the substrate cleaning method of the
exemplary embodiment of the present disclosure, a higher removing
performance of the particles as compared with the topcoat solution
can be obtained in various substrates. Meanwhile, specific
composition etc. of the film-forming treatment solution will be
discussed later.
[0034] Subsequently, as shown in FIG. 1D, to the treatment film
stripped from the wafer W, a dissolving treatment solution capable
of dissolving the treatment film is supplied. By so doing, the
treatment film is dissolved so that the particles P incorporated
into the treatment film becomes in the state of floating in the
dissolving treatment solution. Thereafter, by washing out the
dissolving treatment solution and the dissolved treatment film with
pure water, etc., the particles P can be removed from the surface
of the wafer W (see FIG. 1E).
[0035] As discussed above, in the substrate cleaning method
according to the exemplary embodiment of the present disclosure,
the treatment film formed on the wafer W is stripped from the wafer
W in the state of the "film", so that the particles P attached to
the pattern etc. can be removed together with the treatment film
from the wafer W.
[0036] Therefore, according to the substrate cleaning method of the
exemplary embodiment of the present disclosure, the particle
removal is effected by utilizing the formation and removal of the
treatment film; and thus, erosion of the underlayer film due to an
etching action etc. can be suppressed.
[0037] In addition, according to the substrate cleaning method of
the exemplary embodiment of the present disclosure, the particles P
can be removed by a weaker force as compared with the conventional
substrate cleaning method utilizing a physical force; and thus, the
pattern fall can be suppressed, too.
[0038] Moreover, according to the substrate cleaning method of the
exemplary embodiment of the present disclosure, the particles P
whose particle diameters are small can be removed readily; these
particles having been difficult to be removed by the conventional
substrate cleaning method utilizing a physical force.
[0039] Meanwhile, in the substrate cleaning method according to the
exemplary embodiment of the present disclosure, the treatment film
is entirely removed without performing a patterning exposure after
it is formed on the wafer W. Therefore, the wafer W after cleaning
becomes to the state before application of the film-forming
treatment solution, namely, to the state in which the
pattern-formed surface is exposed.
[Composition for Substrate Cleaning]
[0040] Next, the film-forming treatment solution mentioned above
will be specifically explained. Meanwhile, hereunder, the
film-forming treatment solution is also referred to as a
"composition for substrate cleaning".
[0041] The composition for substrate cleaning contains (A) an
organic solvent and (B) a fluorine-containing polymer that is
soluble in the organic solvent. It is preferable that the polymer
(B) has a partial structure represented by the following formula
(1). It is presumed that because the polymer (B) has a partial
structure represented by the following formula (1) as a polar
group, not only the composition for substrate cleaning can express
suitable wetting and extending properties to the substrate surface
but also the treatment film formed can have an affinity to the
stripping treatment solution as well as a suitable dissolution
rate; and thus, the treatment film can be removed promptly in the
state in which the particles on the substrate surface are enclosed
therein, so that a high removal efficiency can be realized.
##STR00001##
[0042] In the formula (1), R.sup.1 and R.sup.2 each independently
represents a hydrogen atom, a fluorine atom, an alkyl group having
1 to 8 carbon atoms, or a fluorinated alkyl group having 1 to 8
carbon atoms, provided that at least one of R.sup.1 and R.sup.2 is
a fluorine atom or a fluorinated alkyl group having 1 to 8 carbon
atoms, and the symbol * shows a bonding site with another atom
constituting the polymer.
[0043] The composition for substrate cleaning may further contain a
low-molecular organic acid (hereinafter, also referred to as an
"organic acid (C)"). Here, the low-molecular organic acid means an
acid containing one or more carbon atoms in one molecule thereof
and not having a repeating unit formed by a polymerization reaction
or a condensation reaction. The molecular weight thereof is not
restricted; however, it is generally in the range of 40 or more and
2000 or less. When the composition for substrate cleaning contains
the organic acid (C), the composition for substrate cleaning can be
removed more readily from the surface of the substrate. For
example, when the treatment film is formed on a surface of a
silicon nitride substrate having a SiN film as an underlayer film
or on a surface of a titanium nitride substrate having a TiN film
as an underlayer film, removal of the treatment film sometimes
takes more time than when the treatment film is formed on a surface
of a silicon substrate. By adding the organic acid (C), the time
necessary to remove the treatment film can be shortened. The reason
for this is not clear yet, but one possible reason might be
presumed as following; for example, the treatment film formed on
the surface of the substrate becomes to the state in which the
organic acid (C) is dispersed in the polymer (B), thereby
decreasing the strength of the treatment film to a proper strength.
As a result of this, it is presumed that the treatment film can be
removed more readily from the substrate, even if the substrate has
a strong interaction with the polymer (B) such as, for example, a
silicon nitride substrate.
[0044] In addition, besides the components (A) to (C), the
composition for substrate cleaning may contain an arbitrary
component so far as the effects of the present invention are not
damaged.
[0045] Hereunder, each of the components will be explained.
[(A) Organic Solvent]
[0046] The organic solvent (A) is a component capable of dissolving
the polymer (B). When the organic acid (C) is added, it is
preferable that the organic solvent (A) can dissolve the organic
acid (C).
[0047] Illustrative examples of the organic solvent (A) include
organic solvents such as an alcohol solvent, an ether solvent, a
ketone solvent, an amide solvent, an ester solvent, and a
hydrocarbon solvent. The composition for substrate cleaning may
contain a solvent other than the organic solvent (A). Illustrative
examples of the solvent other than the organic solvent (A) include
water.
[0048] Illustrative examples of the alcohol solvent include
monovalent alcohols having 1 to 18 carbon atoms such as ethanol,
isopropyl alcohol, amyl alcohol, 4-methyl-2-pentanol, cyclohexanol,
3,3,5-trimethylcyclohexanol, furfuryl alcohol, benzyl alcohol, and
diacetone alcohol; divalent alcohols having 2 to 12 carbon atoms
such as ethylene glycol, propylene glycol, diethylene glycol,
dipropylene glycol, triethylene glycol, and tripropylene glycol;
and partial ethers of them.
[0049] Illustrative examples of the ether solvent include dialkyl
ether solvents such as diethyl ether, dipropyl ether, dibutyl
ether, and diisoamyl ether; cyclic ether solvents such as
tetrahydrofuran and tetrahydropyran; and aromatic ring-containing
ether solvents such as diphenyl ether and anisole.
[0050] Illustrative examples of the ketone solvent include chain
ketone solvents such as acetone, methyl ethyl ketone,
methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone,
methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone,
methyl-n-hexyl ketone, di-isobutyl ketone, and trimethyl nonanone;
cyclic ketone solvents such as cyclopentanone, cyclohexanone,
cycloheptanone, cyclooctanone, and methyl cyclohexanone;
2,4-pentanedione; acetonyl acetone; and acetophenone.
[0051] Illustrative examples of the amide solvent include cyclic
amide solvents such as N,N'-dimethylimidazolidinone and
N-methylpyrrolidone; and chain amide solvents such as
N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide,
acetamide, N-methylacetamide, N,N-dimethylacetamide, and
N-methylpropionamide.
[0052] Illustrative examples of the ester solvent include
monovalent alcohol carboxylate solvents such as ethyl acetate,
butyl acetate, benzyl acetate, cyclohexyl acetate, and ethyl
lactate; polyvalent alcohol partial ether carboxylate solvents such
as a monocarboxylate of an alkylene glycol monoalkyl ether and a
monocarboxylate of a dialkylene glycol monoalkyl ether; cyclic
ester solvents such as butyrolactone; carbonate solvents such as
diethyl carbonate; and polycarboxylate alkyl ester solvents such as
diethyl oxalate and diethyl phthalate.
[0053] Illustrative examples of the hydrocarbon solvent include
aliphatic hydrocarbon solvents such as n-pentane, iso-pentane,
n-hexane, iso-hexane, n-heptane, iso-heptane,
2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane, and
methylcyclohexane; and aromatic hydrocarbon solvents such as
benzene, toluene, xylene, mesitylene, ethylbenzene,
trimethylbenzene, methylethylbenzene, n-propylbenzene,
iso-propylbenzene, diethybenzene, iso-butylbenzene,
triethylbenzene, di-iso-propylbenzene, and n-amylnaphthalene.
[0054] As to the organic solvent (A), an alcohol solvent, an ether
solvent and an ester solvent are preferable; a monoalcohol solvent,
a dialkyl ether solvent and a monovalent alcohol carboxylate
solvent are more preferable; and 4-methyl-2-pentanol, diisoamyl
ether, propylene glycol monoethyl ether, ethoxypropanol, and ethyl
lactate are still more preferable.
[0055] The content rate of water to the total of the organic
solvent (A) and the water is preferably 20% or less by mass, more
preferably 5% or less by mass, still more preferably 2% or less by
mass, or particularly preferably 0% by mass. When the content rate
of water to the total of the organic solvent (A) and the water is
equal to or lower than the above-mentioned upper limit, the
strength of the formed treatment film can be lowered to a proper
strength, so that the removing performance of the particles can be
enhanced.
[0056] The lower limit of the content of the organic solvent (A) in
the composition for substrate cleaning is preferably 50% by mass,
more preferably 60% by mass, or still more preferably 70% by mass.
The upper limit of the content is preferably 99.9% by mass, more
preferably 99% by mass, or still more preferably 95% by mass. When
the content of the organic solvent (A) is between the upper limit
and the lower limit as mentioned above, the performance of the
composition for substrate cleaning in removing the particles
attached to the silicon nitride substrate can be enhanced
furthermore. The composition for substrate cleaning may contain
one, or two or more of the organic solvent (A).
[(B) Polymer]
[0057] The polymer (B) is a fluorine-containing polymer that is
soluble in the organic solvent (A). It is preferable that the
polymer (B) has a partial structure represented by the following
formula (1):
##STR00002##
[0058] wherein
[0059] R.sup.1 and R.sup.2 each independently represents a hydrogen
atom, a fluorine atom, an alkyl group having 1 to 8 carbon atoms,
or a fluorinated alkyl group having 1 to 8 carbon atoms, provided
that at least one of R.sup.1 and R.sup.2 is a fluorine atom or a
fluorinated alkyl group having 1 to 8 carbon atoms; and the symbol
* shows a bonding site with another atom constituting the
polymer.
[0060] Illustrative examples of the alkyl group represented by
R.sup.1 or R.sup.2, or an alkyl group in the fluorinated alkyl
group represented by R.sup.1 or R.sup.2 (i.e., an alkyl before
being substituted with a fluorine atom) include linear or branched
alkyl groups having 1 to 8 carbon atoms such as methyl, ethyl,
n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, pentyl,
hexyl, heptyl and octyl groups; cycloalkyl groups having 3 to 8
carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl,
cyclohexyl, cycloheptyl and cyclooctyl groups; and alkyl groups
having a linear or branched moiety and a cyclic moiety and having 4
to 8 carbon atoms such as cyclopentylmethyl, cyclopentylethyl,
cyclopentylpropyl, cyclohexylmethyl, and cyclohexylethyl
groups.
[0061] In the fluorinated alkyl group represented by R.sup.1 or
R.sup.2, the hydrogen atoms of the alkyl group having 1 to 8 carbon
atoms may be partially substituted with a fluorine atom(s), or may
be wholly substituted with fluorine atoms. It is preferable that
the fluorinated alkyl group represented by R.sup.1 or R.sup.2 is a
trifluoromethyl group.
[0062] The type of the polymer (B) is not particularly restricted
as long as the polymer (B) has a fluorine atom and is soluble in
the organic solvent (A); however, in view of easiness in the
synthesis thereof and a high removability, a cyclic polyolefin
having a fluorine atom and a poly(meth)acrylate having a fluorine
atom are preferable. When a poly(meth)acrylate having a fluorine
atom is used, a preferable polymer thereof includes the one having
a fluorine-containing structure unit represented by the following
formula (2) (hereinafter, also referred to as "structure unit
(I)").
##STR00003##
[0063] In the formula (2), R' represents a hydrogen atom, a
fluorine atom, a methyl group, or a trifluoromethyl group, and Rf
represents a group represented by the formula (1) or a group having
a partial structure represented by the formula (1).
[0064] As to R' shown above, in view of the copolymerization
ability of the monomer to give the structure unit (I), a hydrogen
atom and a methyl group are preferable, though a methyl group is
more preferable.
[0065] Illustrative examples of the group represented by Rf which
has a partial structure represented by the formula (1) include a
hydrocarbon group substituted with the group represented by the
formula (1). The hydrocarbon group may be substituted with two or
more of the groups represented by the formula (1). Illustrative
examples of a preferable group represented by the formula (1)
include a hydroxy di(trifluoromethyl)methyl group.
[0066] The hydrocarbon group may be a chain hydrocarbon group, an
alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a
combination thereof. The chain hydrocarbon group may be linear or
branched.
[0067] Illustrative examples of the chain hydrocarbon group include
linear or branched alkyl groups such as methyl, ethyl, n-propyl,
isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, pentyl, hexyl,
heptyl, octyl, nonyl and decyl groups. Illustrative examples of the
alicyclic hydrocarbon group include cycloalkyl groups such as
cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,
cyclooctyl, cyclononyl and cyclodecyl groups; and bridged alicyclic
hydrocarbon groups resulting from removal of one hydrogen atom from
norbornane, norbornene, tricyclodecane, tetracyclododecane,
adamantane or the like. Illustrative examples of the aromatic
hydrocarbon group include phenyl, tolyl, xylyl, biphenyl, indenyl,
naphtyl, dimethyl naphtyl, anthryl, phenanthryl, fluorenyl,
pyrenyl, chrysenyl and naphthacenyl groups. Illustrative examples
of a combination of the chain hydrocarbon group and the cyclic
hydrocarbon group include cyclopentylmethyl, cyclopentylethyl,
cyclopentyipropyl, cyclohexylmethyl, cyclohexylethyl,
cyclohexylpropyl, tolyl, xylyl, dimethyl naphty, benzyl,
naphthylmethyl, indenylmethyl and biphenylmethyl groups. The carbon
number of the linear or branched alkyl group is, for example, 1 to
20, or preferably 1 to 10. The carbon number of the cycloalkyl
group is, for example, 3 to 22, or preferably 3 to 12. The carbon
number of the alkyl group having a linear or branched moiety and a
cyclic moiety is, for example, 4 to 23, or preferably 4 to 13.
[0068] Illustrative examples of a preferable group represented by
Rf include hydroxy-substituted fluorinated chain hydrocarbon groups
such as a hydroxy di(trifluoromethyl)methyl group, a hydroxy
di(trifluoromethyl)ethyl group, a hydroxy di(trifluoromethyl)propyl
group, and a hydroxy di(trifluoromethyl)butyl group;
hydroxy-substituted fluorinated alicyclic hydrocarbon groups such
as a hydroxy di(trifluoromethyl)methyl cyclopentyl group and a
hydroxy di(trifluoromethyl)methyl cyclohexyl group; and
hydroxy-substituted fluorinated aromatic hydrocarbon groups such as
a hydroxy di(trifluoromethyl)methyl phenyl group.
[0069] As to Rf, among them, the hydroxy-substituted fluorinated
chain hydrocarbon groups (i.e., alkyl groups substituted with the
group represented by formula (1)) are preferable; and the hydroxy
di(trifluoromethyl)butyl group is more preferable.
[0070] The content of the structure unit (I) is, relative to total
structure units constituting the polymer (B), preferably in the
range of 10 to 100% by mole, more preferably in the range of 50 to
100% by mole, still more preferably in the range of 90 to 100% by
mole, or particularly preferably in the range of 95 to 100% by
mole. When the content of the structure unit (I) is within the
range mentioned above, the removability of the treatment film can
be further enhanced.
[0071] The polymer (B) may further contain, as a structure unit
(II), a structure unit containing a fluoroalkyl group, a structure
unit containing a .beta.-diketone structure, a structure unit
containing a carboxy group, a structure unit containing a sulfo
group, a structure unit containing a sulfonamide group, a structure
unit derived from an alkyl(meth)acrylate, a structure unit
containing a monocyclic or polycyclic lactone skeleton, a structure
unit containing a hydroxy group, a structure unit containing an
aromatic ring, or a structure unit containing an acid-dissociable
group. When the structure unit (II) contains a fluoroalkyl group,
the content of the structure unit (II) in the polymer (B) is
preferably 50% or less by mole, more preferably less than 30% by
mole, or particularly preferably less than 10% by mole. When the
content of the structure unit (II) containing the fluoroalkyl group
is more than 50% by mole, especially when the content of the
structure unit (II) containing the fluoroalkyl group is more than
50% by mole and an organic acid (C) discussed later is not added,
the removability of the treatment film is prone to be
deteriorated.
[0072] The acid dissociation constant of the polymer (B) is
preferably less than the acid dissociation constant of the organic
acid (C) that will be discussed later. When the acid dissociation
constant of the polymer (B) is less than that of the organic acid
(C), the removability of the treatment film from the substrate
surface can be enhanced furthermore. The acid dissociation
constants of the polymer (B) and the organic acid (C) can be
determined by a heretofore known titration method. To evaluate the
relative magnitude relation between the acid dissociation
constants, the values may be obtained from the calculation by using
a chemical calculation software as the more convenient method than
the titration method. For example, they can be calculated by using
the program provided by ChemAxon Ltd.
[0073] The lower limit of the content of the polymer (B) in the
composition for substrate cleaning is preferably 0.1% by mass, more
preferably 0.5% by mass, or still more preferably 1% by mass. The
upper limit of the content is preferably 50% by mass, more
preferably 30% by mass, or still more preferably 15% by mass. When
the content is between the upper limit and the lower limit as
mentioned above, the removability of the treatment film from the
substrate surface can be enhanced furthermore.
[0074] The lower limit of the content of the polymer (B) relative
to total solid components in the composition for substrate cleaning
is preferably 30% by mass, more preferably 40% by mass, or still
more preferably 50% by mass. The upper limit of the content is
preferably 99% by mass, more preferably 98% by mass, or still more
preferably 96% by mass.
[(C) Organic Acid]
[0075] The composition for substrate cleaning may further contain
(C) an organic acid. When the organic acid (C) is added, the
treatment film formed on the substrate surface can be removed more
readily. Preferably, the organic acid (C) is not a polymer. Here,
the phrase "not a polymer" means that it does not have a repeating
unit. The upper limit of the molecular weight of the organic acid
(C) is, for example, 500, preferably 400, or more preferably 300.
The lower limit of the molecular weight of the organic acid (C) is,
for example, 50, or preferably 55.
[0076] Illustrative examples of the organic acid (C) include
monocarboxylic acids such as acetic acid, propionic acid, butyric
acid, pentanoic acid, hexanoic acid, cyclohexane carboxylic acid,
cyclohexylacetic acid, 1-adamantane carboxylic acid, benzoic acid,
and phenylacetic acid; fluorine-containing monocarboxylic acids
such as difluoroacetic acid, trifluoroacetic acid,
pentafluoropropionic acid, heptafluorobutyric acid,
fluorophenylacetic acid, and difluorobenzoic acid;
heteroatom-containing monocarboxylic acids such as
10-hydroxydecanoic acid, thiolacetic acid, 5-oxohexanoic acid,
3-methoxy cyclohexane carboxylic acid, camphor carboxylic acid,
dinitrobenzoic acid, and nitrophenylacetic acid; monocarboxylic
acids such as double bond-containing monocarboxylic acids including
(meth)acrylic acid, crotonic acid, and cinnamic acid;
polycarboxylic acids such as oxalic acid, malonic acid, succinic
acid, glutaric acid, adipic acid, dodecane dicarboxylic acid,
propane tricarboxylic acid, butane tetracarboxylic acid,
hexafluoroglutaric acid, cyclohexane hexacarboxylic acid, and
1,4-naphthalene dicarboxylic acid; and partial esters of the
polycarboxylic acids mentioned above.
[0077] The lower limit of the solubility of the organic acid (C) in
water at 25.degree. C. is preferably 5% by mass, more preferably 7%
by mass, or still more preferably 10% by mass. The upper limit of
the solubility is preferably 50% by mass, more preferably 40% by
mass, or still more preferably 30% by mass. When the solubility is
between the upper limit and the lower limit as mentioned above, the
removability of the formed treatment film can be enhanced
furthermore.
[0078] The organic acid (C) is preferably in the solid state at
25.degree. C. If the organic acid (C) is in the solid state at
25.degree. C., it is considered that the organic acid (C) in the
solid state is precipitated in the treatment film formed from the
composition for substrate cleaning, so that the removability
thereof can be enhanced furthermore.
[0079] In order for the treatment film to be removed more readily,
the organic acid (C) is preferably polycarboxylic acids, or more
preferably oxalic acid, malic acid, and citric acid.
[0080] The lower limit of the content of the organic acid (C) in
the composition for substrate cleaning is preferably 0.01% by mass,
more preferably 0.05% by mass, or still more preferably 0.1% by
mass. The upper limit of the content is preferably 30% by mass,
more preferably 20% by mass, or still more preferably 10% by
mass.
[0081] The lower limit of the content of the organic acid (C)
relative to the total solid components in the composition for
substrate cleaning is preferably 0.5% by mass, more preferably 1%
by mass, or still more preferably 3% by mass. The upper limit of
the content is preferably 30% by mass, more preferably 20% by mass,
or still more preferably 10% by mass.
[0082] When the content of the organic acid (C) is between the
upper limit and the lower limit as mentioned above, the treatment
film can be removed more readily.
[Arbitrary Components]
[0083] The composition for substrate cleaning may contain an
arbitrary component other than the components (A) to (C) mentioned
above. Illustrative examples of the arbitrary component include
surfactant, etc.
[0084] Illustrative examples of the surfactant include nonionic
surfactants such as polyoxyethylene lauryl ether, polyoxyethylene
stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octyl
phenyl ether, polyoxyethylene n-nonyl phenyl ether, polyethylene
glycol dilaurate, and polyethylene glycol distearate.
[0085] The content of the surfactant mentioned above is usually 2%
or less by mass, or preferably 1% or less by mass.
[Structure of the Substrate Cleaning System]
[0086] Next, the structure of the substrate cleaning system
according to the exemplary embodiment of the present disclosure
will be explained by using FIG. 3. FIG. 3 is a schematic diagram
illustrating the structure of the substrate cleaning system
according to the exemplary embodiment of the present disclosure. In
the following, in order to clarify positional relationships, the
X-axis, Y-axis, and Z-axis which are orthogonal to each other will
be defined. The positive Z-axis direction will be regarded as a
vertically upward direction.
[0087] As shown in FIG. 3, a substrate cleaning system 1 includes a
carry-in/out station 2 and a processing station 3. The carry-in/out
station 2 and the processing station 3 are provided adjacent to
each other.
[0088] The carry-in/out station 2 is provided with a carrier
placing section 11 and a transfer section 12. In the carrier
placing section 11, a plurality of transfer vessels (hereinafter,
referred to as "carriers C") are placed to accommodate a plurality
of wafers W horizontally.
[0089] The transfer section 12 is provided adjacent to the carrier
placing section 11. Inside the transfer section 12, a substrate
transfer device 121 and a delivery unit 122 are provided.
[0090] The substrate transfer device 121 is provided with a wafer
holding mechanism configured to hold the wafer W. Further, the
substrate transfer device 121 is movable horizontally and
vertically and pivotable around a vertical axis, and transfers the
wafer W between the carrier C and the delivery unit 122 by using
the wafer holding mechanism.
[0091] The processing station 3 is provided adjacent to the
transfer section 12. The processing station 3 is provided with a
transfer section 13 and a plurality of substrate cleaning devices
14. The plurality of substrate cleaning devices 14 are arranged at
both sides of the transfer section 13.
[0092] The transfer section 13 is provided with a substrate
transfer device 131 therein. The substrate transfer device 131 is
provided with a wafer holding mechanism configured to hold the
wafer W. Further, the substrate transfer device 131 is movable
horizontally and vertically and pivotable around a vertical axis,
and transfers the wafer W between the delivery unit 122 and the
substrate cleaning devices 14 by using the wafer holding
mechanism.
[0093] The substrate cleaning device 14 is a device configured to
perform the substrate cleaning process based on the substrate
cleaning method mentioned above. The specific structure of the
substrate cleaning device 14 will be discussed later.
[0094] Further, the substrate cleaning system 1 is provided with a
control device 4. The control device 4 is a device configured to
control the operation of the substrate cleaning system 1. The
control device 4 is, for example, a computer, and includes a
control unit 15 and a storage unit 16. The storage unit 16 stores a
program that controls various processes such as the substrate
cleaning process. The control unit 15 controls the operation of the
substrate cleaning system 1 by reading and executing the program
stored in the storage unit 16. The control unit 15 comprises, for
example, CPU (Central Processing Unit) and MPU (Micro Processor
Unit); and the storage unit 16 comprises, for example, ROM (Read
Only Memory) and RAM (Random Access Memory).
[0095] Meanwhile, the program may be recorded in a
computer-readable recording medium, and installed from the recoding
medium to the storage unit 16 of the control device 4. The
computer-readable recording medium may be, for example, a hard disk
(HD), a flexible disk (FD), a compact disc (CD), a magnet optical
disc (MO), or a memory card.
[0096] In the substrate cleaning system 1 configured as described
above, the substrate transfer device 121 of the carry-in/out
station 2 first takes out a wafer W from the carrier C, and then
places the taken wafer W on the delivery unit 122. The wafer W
placed on the delivery unit 122 is taken out from the delivery unit
122 by the substrate transfer device 131 of the processing station
3 and carried into the substrate cleaning device 14; and then, the
substrate cleaning process is performed by the substrate cleaning
device 14. The wafer W after being cleaned is carried out from the
substrate cleaning device 14 by the substrate transfer device 131,
and then placed on the delivery unit 122, and then returned to the
carrier C by the substrate transfer device 121.
[Structure of the Substrate Cleaning Device]
[0097] Next, the structure of the substrate cleaning device 14 will
be explained by referring to FIG. 4. FIG. 4 is a schematic diagram
illustrating the structure of the substrate cleaning device 14
according to the exemplary embodiment of the present
disclosure.
[0098] As shown in FIG. 4, the substrate cleaning device 14 is
provided with a chamber 20, a substrate holding mechanism 30, a
solution supply unit 40, and a recovery cup 50.
[0099] The chamber 20 accommodates the substrate holding mechanism
30, the solution supply unit 40, and the recovery cup 50. On the
ceiling of the chamber 20, a FFU (Fan Filter Unit) 21 is provided.
The FFU 21 forms a downflow in the chamber 20.
[0100] The FFU 21 is connected to a downflow gas source 23 via a
valve 22. The FFU 21 discharges a downflow gas (for example, a dry
air) supplied from the downflow gas source 23 into the chamber
20.
[0101] The substrate holding mechanism 30 is provided with a
rotation holding unit 31, a support unit 32, and a driving unit 33.
The rotation holding unit 31 is arranged in an almost central part
of the chamber 20. Above the rotation holding unit 31 is arranged a
holding member 311 configured to hold the wafer W from the side
thereof. The wafer W is held horizontally by the holding member 311
above the rotation holding unit 31 with a small space from it.
[0102] The support unit 32 is a member extended vertically whose
base end portion is held rotatably by the driving unit 33 while
holding the rotation holding unit 31 horizontally in its tip end
portion. The driving unit 33 rotates the support unit 32 around the
vertical axis.
[0103] By rotating the support unit 32 by using the driving unit
33, the substrate holding mechanism 30 rotates the rotation holding
unit 31 supported by the support unit 32, thereby rotating the
wafer W held on the rotation holding unit 31.
[0104] A solution supply unit 40 supplies various treatment
solutions to the wafer W held on the substrate holding mechanism
30. The solution supply unit 40 is provided with a nozzle 41, an
arm 42 configured to hold the nozzle 41 horizontally, and a
pivoting, raising and lowering mechanism 43 to pivot, raise and
lower the arm 42.
[0105] The nozzle 41 is connected to each of a film-forming
treatment solution source 45a, a DIW source 45b, and an alkaline
aqueous solution source 45c via valves 44a to 44c, respectively.
Meanwhile, in the exemplary embodiment of the present disclosure,
the number of the nozzle 41 in the solution supply unit 40 is one;
however, two or more nozzles may be installed. For example, four
nozzles may be installed in order to separately supply each of the
different treatment solutions.
[0106] The solution supply unit 40 is configured as mentioned above
and supplies the film-forming treatment solution (the composition
for substrate cleaning), DIW, or the alkaline aqueous solution to
the wafer W.
[0107] DIW is one example of the stripping treatment solution
capable of stripping the treatment film from the wafer W.
Meanwhile, DIW is used also as a rinsing treatment solution in a
rinsing process after the dissolving treatment solution supplying
process which will be discussed later.
[0108] The alkaline aqueous solution is one example of the
dissolving treatment solution capable of dissolving the treatment
film. The alkaline aqueous solution is, for example, an alkaline
developing solution. As to the alkaline developing solution, any
solution will do so long as it contains at least one of, for
example, an aqueous ammonia solution, a quaternary ammonium
hydroxide solution such as tetramethyl ammonium hydroxide (TMAH),
and an aqueous choline solution.
[0109] The recovery cup 50 is arranged such that it surrounds the
rotation holding unit 31, so that the treatment solution scattered
from the wafer W by rotation of the rotation holding unit 31 can be
collected. On the bottom of the recovery cup 50 is formed a drain
port 51; and the treatment solution collected by the recovery cup
50 is discharged to outside the substrate cleaning device 14
through the drain port 51. Further, in the bottom part of the
recovery cup 50 is formed an exhaust port 52 configured to
discharge the downflow gas supplied from the FFU 21 to outside the
substrate cleaning device 14.
[Specific Operation of the Substrate Cleaning System]
[0110] Next, the specific operation of the substrate cleaning
device 14 will be explained by referring to FIG. 5. FIG. 5 is a
flow chart showing a processing procedure of the substrate cleaning
process performed by the substrate cleaning system 1 according to
the exemplary embodiment of the present disclosure. Each of the
devices provided in the substrate cleaning system 1 performs each
processing procedure shown in FIG. 5 by control of the control unit
15.
[0111] Hereunder, the explanation will be made as to the substrate
cleaning process when any of the compositions of Examples 12 to 16
discussed later is used as the film-forming treatment solution.
[0112] As shown in FIG. 5, in the substrate cleaning device 14, at
first, a substrate carrying-in process is performed (step S101). In
this substrate carrying-in process, the wafer W which is carried
into the chamber 20 by the substrate transfer device 131 (see FIG.
3) is held by the holding member 311 of the substrate holding
mechanism 30. At this time, the wafer W is held to the holding
member 311 in such a state that the pattern-formed surface may be
faced upward. Thereafter, the rotation holding unit 31 rotates by
the driving unit 33. By so doing, the wafer W rotates together with
the rotation holding unit 31 while it is held horizontally to the
rotation holding unit 31.
[0113] Subsequently, in the substrate cleaning device 14, a
film-forming treatment solution supplying process is performed
(step S102). In this film-forming treatment solution supplying
process, the nozzle 41 of the solution supply unit 40 is placed
above the center of the wafer W. Thereafter, by opening the valves
44a for a prescribed period of time, the film-forming treatment
solution is supplied to the pattern-formed surface of the wafer W
not formed with a resist. In this way, the film-forming treatment
solution is supplied onto the wafer W without intervened by the
resist.
[0114] The film-forming treatment solution supplied to the wafer W
is spread on the surface of the wafer W by a centrifugal force
generated by the rotation of the wafer W. In this way, a liquid
film of the film-forming treatment solution is formed on the
pattern-formed surface of the wafer W. The film thickness of the
treatment film to be formed is preferably in the range of 10 to
5,000 nm, or more preferably in the range of 20 to 500 nm.
[0115] Subsequently, in the substrate cleaning device 14, a drying
process is performed (step S103). In this drying process, the
film-forming treatment solution is dried, for example, by
increasing the rotation speed of the wafer W during a prescribed
period of time. In this way, for example, part or all of the
organic solvent contained in the film-forming treatment solution is
evaporated so that the solid components contained in the
film-forming treatment solution are solidified or cured, thereby
the treatment film is formed on the pattern-formed surface of the
wafer W.
[0116] Meanwhile, though not shown by the drawing, the drying
process of the step S103 may be, for example, the process wherein
inside the chamber 20 is brought to the state of a reduced pressure
by means of a vacuuming device, or the process wherein the humidity
inside the chamber 20 is lowered by the downflow gas supplied from
the FFU 21. With these processes too, the film-forming treatment
solution may be solidified or cured.
[0117] Alternatively, in the substrate cleaning device 14, the
wafer W may be allowed to stand in the substrate cleaning device 14
until the film-forming solution is solidified or cured naturally.
Further alternatively, by stopping the rotation of the wafer W, or
by rotating the wafer W with the rotation speed at which the
surface of the wafer W is not exposed by spinning out the
film-forming treatment solution, the film-forming treatment
solution may be solidified or cured.
[0118] Subsequently, in the substrate cleaning device 14, a
stripping treatment solution supplying process is performed (step
S104). In this stripping treatment solution supplying process, by
opening the valve 44b for a prescribed period of time, DIW, which
is a stripping treatment solution, is supplied to the treatment
film formed on the wafer W. DIW supplied to the treatment film is
spread on the treatment film by a centrifugal force generated by
rotation of the wafer W.
[0119] DIW is penetrated into the treatment film and reaches the
interface between the treatment film and the wafer W, whereby
stripping the treatment film from the wafer W. In this way, the
particles P attached to the pattern-formed surface of the wafer W
are removed from the wafer W together with the treatment film.
[0120] Here, as mentioned above, the film-forming treatment
solution contains the organic solvent and the fluorine-containing
polymer that is soluble in the organic solvent (preferably, the
polymer having the partial structure represented by the formula
(1)). By using the film-forming treatment solution like this, the
removability of the treatment film from the wafer W is enhanced, so
that the removing performance of the particles P on the wafer W can
be enhanced.
[0121] Further, because the film-forming treatment solution has a
high removability of the treatment film, it is conceived that this
can be applied to substrates formed of various materials.
Illustrative examples of the applicable substrate include metal or
semi-metal substrates such as a silicon substrate, an aluminum
substrate, a nickel substrate, a chromium substrate, a molybdenum
substrate, a tungsten substrate, a copper substrate, a tantalum
substrate, and a titanium substrate; and ceramic substrates such as
a silicon nitride substrate, an alumina substrate, a silicon
dioxide substrate, a tantalum nitride substrate, and a titanium
nitride substrate. Among them, a silicon substrate, a silicon
nitride substrate, and a titanium nitride substrate are preferable;
however, a silicon nitride substrate is more preferable.
[0122] Subsequently, in the substrate cleaning device 14, a
dissolving treatment solution supplying process is performed (step
S105). In this dissolving treatment solution supplying process, by
opening the valve 44c for a prescribed period of time, the alkaline
aqueous solution, which is a dissolving treatment solution, is
supplied to the treatment film stripped from the wafer W. In this
way, the treatment film is dissolved.
[0123] Here, as the dissolving treatment solution, for example, an
organic solvent such as a thinner and an alkaline aqueous solution
such as an alkaline developing solution may be used. Meanwhile,
when the alkaline aqueous solution is used as the dissolving
treatment solution, the zeta potential having the same polarity in
the wafer W and the particles P can be generated. With this, the
wafer W and the particles P repel with each other, so that
reattachment of the particles P to the wafer W can be avoided. The
stripping treatment solution supplying process of the step S104 and
the dissolving treatment solution supplying process of the step
S105 correspond to one example of the removing solution supply step
of supplying to the treatment film formed on the substrate by
solidification or curing of the film-forming treatment solution,
the removing solution capable of removing the treatment film.
[0124] Subsequently, in the substrate cleaning device 14, a rinsing
process is performed (step S106). In this rinsing process, by
opening the valve 44b for a prescribed period of time, DIW is
supplied as a rinsing solution to the rotating wafer W. In this
way, the dissolved treatment film and the particles P floating in
the alkaline aqueous solution are removed from the wafer W together
with DIW.
[0125] Subsequently, in the substrate cleaning device 14, a drying
process is performed (step S107). In this drying process, for
example, by increasing the rotation speed of the wafer W during a
prescribed period of time, DIW which is left on the surface of the
wafer W is span off to dry the wafer W. Thereafter, the rotation of
the wafer W is stopped.
[0126] Subsequently, in the substrate cleaning device 14, a
substrate carrying-out process is performed (step S108). In this
substrate carrying-out process, by means of the substrate transfer
device 131 (see FIG. 3), the wafer W is taken out from the chamber
20 of the substrate cleaning device 14. Thereafter, the wafer W is
accommodated in the carrier C which is placed in the carrier
placing section 11 via the delivery unit 122 as well as the
substrate transfer device 121. When the substrate carrying-out
process is over, the substrate cleaning process of the wafer W
(i.e., the substrate cleaning process of one wafer) is
completed.
[0127] As discussed above, the substrate cleaning method according
to the exemplary embodiment of the present disclosure comprises the
film-forming treatment solution supply step and the removing
solution supply step. In the film-forming treatment solution supply
step, the film-forming treatment solution containing the organic
solvent and the fluorine-containing polymer that is soluble in the
organic solvent (more preferably, the polymer having the partial
structure represented by the formula (1) as mentioned above) is
supplied to the substrate. In the film-forming treatment solution
supply step (corresponding to the stripping treatment solution
supplying process and the dissolving treatment solution supplying
process), the removing solution (corresponding to the stripping
treatment solution and the dissolving treatment solution) capable
of removing the treatment film is supplied to the treatment film
formed by solidification or curing of the film-forming treatment
solution on the substrate.
[0128] Therefore, according to the substrate processing system 1 of
the exemplary embodiment of the present disclosure, a high removing
performance of the particles can be obtained.
Other Exemplary Embodiments
[0129] In the exemplary embodiments discussed above, the
film-forming treatment solution supplying process and the
dissolving treatment solution supplying process are performed in
the same chamber; however, alternatively, the film-forming
treatment solution supplying process and the dissolving treatment
solution supplying process may be performed in different chambers.
In this case, for example, a first substrate cleaning device
configured to perform the step S101 (substrate carrying-in process)
to step S103 (drying process) shown in FIG. 5 and a second
substrate cleaning device configured to perform the step S104
(stripping treatment solution supplying process) to step S108
(substrate carrying-out process) shown in FIG. 5 may be arranged in
the processing station 3 shown in FIG. 3. Further alternatively,
the stripping treatment solution supplying process and the
dissolving treatment solution supplying process may be performed in
different chambers.
[0130] In the exemplary embodiments discussed above, the examples
wherein DIW in the liquid state is used as the stripping treatment
solution have been explained; however, the stripping treatment
solution may be DIW in the mist state as well.
[0131] Further, in the exemplary embodiments discussed above, the
examples wherein DIW is supplied directly to the treatment film by
using the nozzle have been explained; however, by raising the
humidity in the chamber by using, for example, a humidifier, DIW
may be supplied indirectly to the treatment film.
[0132] Further, in the exemplary embodiments discussed above, the
examples wherein DIW which is pure water with a normal temperature
is used as the stripping treatment solution have been explained;
however, for example, a heated pure water may be used as the
stripping treatment solution as well. With this, the removing
performance of the treatment film can be enhanced furthermore.
[0133] Further, in the exemplary embodiments discussed above, the
examples wherein DIW is used as the stripping treatment solution
have been explained. However, as far as the process wherein the
treatment film formed on the wafer W is stripped without dissolving
it (or before dissolving it) is feasible, any stripping treatment
solution may be used. For example, the stripping treatment solution
containing at least one of a CO.sub.2 water (DIW mixed with
CO.sub.2 gas), an acidic or alkaline aqueous solution, an aqueous
solution to which a surfactant is added, a fluorine-based solvent
such as HFE (hydrofluoroether), and diluted IPA (IPA (isopropyl
alcohol) diluted with pure water) may be used.
[0134] Further, in the substrate cleaning device, before performing
the film-forming treatment solution supplying process, as a solvent
having an affinity with the film-forming treatment solution, for
example, MIBC (4-methyl-2-pentanol) may be supplied to the wafer W.
MIBC is contained in the film-forming treatment solution so that it
has an affinity with the film-forming treatment solution.
Meanwhile, as the solvent having an affinity with the film-forming
treatment solution other than MIBC, for example, PGME (propylene
glycol monomethyl ether), PGMEA (propylene glycol monomethyl ether
acetate), etc. may be used as well.
[0135] By spreading MIBC having an affinity with the film-forming
treatment solution on the wafer W in advance in the way as
mentioned above, in the film-forming treatment solution supplying
process, the film-forming treatment solution not only can be spread
readily on the surface of the wafer W but also can be penetrated
readily into the space between the patterns. Accordingly, not only
the use amount of the film-forming treatment solution can be
reduced but also the particles P entered into the space between the
patterns can be removed more surely. In addition, the processing
time of the film-forming treatment solution supplying process can
be made shorter.
[0136] In all the exemplary embodiments discussed above, the
explanation was made with regard to the examples in which an
alkaline developing solution is used as the dissolving treatment
solution supplying process; however, the dissolving treatment
solution may also be the alkaline developing solution to which a
hydrogen peroxide aqueous solution is added. By adding the hydrogen
peroxide aqueous solution to the alkaline developing solution as
mentioned above, the surface-roughing of the surface of the wafer W
due to the alkaline developing solution may be suppressed.
[0137] Further, the dissolving treatment solution may be an organic
solvent such as MIBC (4-methyl-2-pentanol), a thinner, toluene,
acetate esters, alcohols, and glycols (propylene glycol monomethyl
ether), or an acidic developing solution such as acetic acid,
formic acid, and hydroxyacetic acid.
[0138] Furthermore, the dissolving treatment solution may contain a
surfactant. Because the surfactant can weaken a surface tension
force, reattachment of the particles P to the wafer W etc. can be
suppressed. Unwanted substances to be removed may include not only
the particles P but also, for example, a substance such as a
polymer which is left on the substrate after dry etching or after
ashing.
EXAMPLES
[0139] Next, Examples of the composition for substrate cleaning
will be explained.
[0140] The weight-average molecular weight (Mw) and the
number-average molecular weight (Mn) of the obtained polymer were
measured by using the GPC column (manufactured by Tosoh Corp.; two
columns of G2000 HXL, one column of G3000 HXL, and one column of
G4000 HXL), with the flow rate of 1.0 mL/minute, the eluting
solvent of tetrahydrofuran, the sample concentration of 1.0% by
mass, the sample injection amount of 100 .mu.L, the column
temperature of 40.degree. C., and the detector of a differential
refractometer, based on the gel permeation chromatography (GPC) by
using the monodisperse polystyrene as the standard. The dispersity
(Mw/Mn) was calculated from the measurement results of Mw and
Mn.
[Synthesis of Polymers]
[0141] Compounds used as the raw materials of the polymers are
shown below.
##STR00004## ##STR00005## ##STR00006##
Production Example 1
[0142] A monomer solution was prepared by dissolving 100 g (100% by
mole) of the compound (M-1) and 7.29 g (7% by mole) of
azobis-iso-butyronitrile (AIBN) into 100 g of 2-butanone. A 1000-mL
three-necked flask charged with 100 g of 2-butanone was purged with
a nitrogen gas for 30 minutes. After the nitrogen purge, the flask
was heated to 80.degree. C.; and then, the monomer solution was
gradually dropped by using a dropping funnel with stirring for the
period of 3 hours. By taking the start of the dropping as the
starting time of the polymerization, the polymerization was carried
out for 6 hours. After the polymerization, the reaction solution
was cooled to 30.degree. C. or lower. The reaction solution was
concentrated under reduced pressure until the mass thereof reached
150 g. Then, 150 g of methanol and 750 g of n-hexane were added for
the phase separation. After the separation, the lower phase was
recovered. To the recovered lower phase, 750 g of n-hexane was
added; and again the phase separation was carried out for
purification. After the separation, the lower phase was recovered.
From the recovered lower phase, the solvent was removed, and then
4-methyl-2-pentanol was added to obtain a solution containing the
resin (P-1). The results thereof are shown in Table 1.
Production Examples 2 to 10
[0143] Production Example 1 was repeated, except that the compounds
to be used and the combination thereof were changed in accordance
with those shown in Table 1, to obtain the resins (P-2) to
(P-10).
TABLE-US-00001 TABLE 1 Composition Weight-average Production ratio
Yield molecular weight Disper- Example Resin (mol %) (%) (Mw) sity
1 P-1 M-1(100) 80 10,500 1.52 2 P-2 M-2(100) 79 10,400 1.51 3 P-3
M-3(100) 80 10,000 1.55 4 P-4 M-4/M-5(70/30) 80 10,520 1.53 5 P-5
M-1/M-6(90/10) 81 9,900 1.5 6 P-6 M-4/M-6(80/20) 78 10,200 1.51 7
P-7 M-6/M-8(50/50) 79 10,450 1.52 8 P-8 M-3/M-6(70/30) 82 10,000
1.52 9 P-9 M-9/M-10(50/50) 84 7,400 1.35 10 P-10 M-11/M-12/M-13 90
80,000 1.85 (30/40/30)
Example 1
[0144] A homogeneous solution was prepared by mixing 100 parts by
mass of the polymer (P-1) and 7,400 parts by mass of
4-methyl-2-pentanol. This solution was filtrated by using a filter
made of HDPE (PhotoKleen EZD, manufactured by Nippon Pall Corp.;
pore diameter of 5 nm). It was confirmed that the number of the
particles with the size of 150 .mu.m or less in the solution was
decreased to 10 particles/mL by the solution particle counter
(KS-41B, manufactured by RION Co., Ltd.) to obtain the composition
for substrate cleaning (D-1). The solid content concentration
thereof was about 1.5%.
Examples 2 to 8 and Comparative Examples 1 and 2
[0145] Example 1 was repeated except that the resin was changed to
those shown in Table 2 to obtain the compositions for substrate
cleaning (D-2) to (D-8) and the comparative compositions (c-1) and
(c-2).
Example 9
[0146] A homogeneous solution was prepared by mixing 100 parts by
mass of the polymer (P-1), 5.0 parts by mass of tartaric acid
(Ac-1) as an organic acid, and 7,400 parts by mass of
4-methyl-2-pentanol. This solution was filtrated by using a filter
made of HDPE (PhotoKleen EZD, manufactured by Nippon Pall Corp.;
pore diameter of 5 nm). It was confirmed that the number of the
particles with the size of 150 .mu.m or less in the solution was
decreased to 10 particles/mL by the solution particle counter
(KS-41B, manufactured by RION Co., Ltd.) to obtain the composition
for substrate cleaning (D-1). The solid content concentration
thereof was about 1.5%.
Examples 10 to 16 and Comparative Examples 3 to 5
[0147] Example 9 was repeated except that the resin and the organic
acid were changed to those shown in Table 2 to obtain the
compositions for substrate cleaning (D-10) to (D-16) and the
comparative compositions (c-3) to (c-5).
TABLE-US-00002 TABLE 2 Resin Organic acid Parts by Parts by Run
Composition Kind mass Kind mass Example 1 D-1 P-1 100 -- -- Example
2 D-2 P-2 100 -- -- Example 3 D-3 P-3 100 -- -- Example 4 D-4 P-4
100 -- -- Example5 D-5 P-5 100 -- -- Example 6 D-6 P-6 100 -- --
Example 7 D-7 P-7 100 -- -- Example 8 D-8 P-8 100 -- -- Example 9
D-9 P-1 100 Ac-1 5 Example 10 D-10 P-2 100 Ac-2 5 Example 11 D-11
P-3 100 Ac-3 5 Example 12 D-12 P-4 100 Ac-4 5 Example 13 D-13 P-5
100 Ac-5 5 Example 14 D-14 P-6 100 Ac-6 5 Example 15 D-15 P-7 100
Ac-7 5 Example 16 D-16 P-8 100 Ac-8 5 Comparative c-1 P-9 100 -- --
Example 1 Comparative c-2 P-10 100 -- -- Example 2 Comparative c-3
P-9 100 Ac-1 5 Example 3 Comparative c-4 P-9 100 Ac-9 5 Example 4
Comparative c-5 P-10 100 Ac-2 5 Example 5
[0148] The organic acids used in each of Examples and Comparative
Examples are shown below. In these Examples, all the organic acids
are the reagents manufactured by Wako Pure Chemical Industries,
Ltd. [0149] Ac-1: tartaric acid [0150] Ac-2: oxalic acid [0151]
Ac-3: citric acid
[0152] Ac-4: maleic acid [0153] Ac-5: malic acid [0154] Ac-6:
fumaric acid [0155] Ac-7: isophthalic acid [0156] Ac-8:
terephthalic acid [0157] Ac-9: polyacrylic acid (Polyacrylic acid
5000, manufactured by Wako Pure Chemical Industries, Ltd.)
[Evaluation of the Particle Removability and the Film
Removability]
[0158] On the 12-inch wafer previously attached with silica
particles having the particle diameter of 200 nm was formed the
treatment film of each composition by a spin coating method by
using the substrate cleaning device 14. To the wafer formed with
the treatment film, a tetramethyl ammonium hydroxide aqueous
solution (TMAH solution) with the concentration of 2.38% by mass
was supplied as a dissolving treatment solution to remove the
treatment film. The removability thereof was judged as "A" if
removal of all the treatment film was completed within 20 seconds
from the start of the supply of the TMHA solution, as "B" if the
removal was completed over 20 seconds and within 1 minute, and as
"C" if the removal was not completed within 1 minute. Further, the
number of the silica particles remained on the wafer after removal
of the treatment film was analyzed by using a dark field defect
inspection device (SP2, manufactured by KLA-Tencor Corp.). It was
judged as "A" if the removing rate of the silica particles was 70%
or more, as "B" if the removing rate was 30% or more and less than
70%, and as "C" if the removing rate was less than 30%. Meanwhile,
if the treatment film could not be formed, the description of
"Inapplicable" was made in the particle removability column.
Evaluation Examples 1 to 16 and Comparative Evaluation Examples 1
to 5
[0159] By using the silicon wafer as the wafer and each of the
compositions for substrate cleaning (D-1) to (D-16) as well as the
comparative compositions (c-1) to (c-5), the particle removability
and the film removability were evaluated in accordance with the
evaluation method mentioned above. These results are shown in Table
3.
TABLE-US-00003 TABLE 3 Compo- Particle Film Run sition removability
removability Evaluation Example 1 D-1 A A Evaluation Example 2 D-2
A A Evaluation Example 3 D-3 B A Evaluation Example 4 D-4 A A
Evaluation Example 5 D-5 A B Evaluation Example 6 D-6 A B
Evaluation Example 7 D-7 A B Evaluation Example 8 D-8 B B
Evaluation Example 9 D-9 A A Evaluation Example 10 D-10 A A
Evaluation Example 11 D-11 A A Evaluation Example 12 D-12 A A
Evaluation Example 13 D-13 A A Evaluation Example 14 D-14 A A
Evaluation Example 15 D-15 A A Evaluation Example 16 D-16 A A
Comparative Evaluation c-1 C C Example 1 Comparative Evaluation c-2
C A Example 2 Comparative Evaluation c-3 C C Example 3 Comparative
Evaluation c-4 Inapplicable Inapplicable Example 4 Comparative
Evaluation c-5 C A Example 5
Evaluation Examples 17 to 24 and Comparative Evaluation Examples 6
and 7
[0160] The particle removability and the film removability were
evaluated in the same way as before except that the silicon wafer
was changed to silicon nitride or to titanium nitride and that the
combination thereof with the composition for substrate cleaning was
changed to those shown in Table 4. These results are shown in Table
4.
TABLE-US-00004 TABLE 4 Wafer material SiN TiN Particle Film
Particle Film Compo- remov- remov- remov- remov- Run sition ability
ability ability ability Evaluation D-9 A A A A Example 17
Evaluation D-10 A A A A Example 18 Evaluation D-11 A A A A Example
19 Evaluation D-12 A A A A Example 20 Evaluation D-13 A B A B
Example 21 Evaluation D-14 A B A B Example 22 Evaluation D-15 A B A
B Example 23 Evaluation D-16 A B A B Example 24 Comparative c-3 C C
C C Evaluation Example 6 Comparative c-4 Inapplic- Inapplic-
Inapplic- Inapplic- Evaluation able able able able Example 7
[0161] From the comparison between each of Evaluation Examples and
Comparative Evaluation Examples, it can be seen that the
composition for substrate cleaning according to the present
invention is excellent in both the particle removability and the
film removability in the substrate cleaning method wherein the film
is formed on the substrate surface and then removed. Further, from
the comparison between Evaluation Examples 5 to 8 and Comparative
Evaluation Examples 13 to 16, it can be seen that the film
removability can be enhanced furthermore by adding the organic
acids.
Evaluation Examples 25 to 31 and Comparative Evaluation Example
8
[0162] The procedure of Evaluation Examples 4, 5, and 12 to 16, and
Comparative Evaluation Example 3 was repeated except that pure
water was used as a stripping treatment solution in place of the
dissolving treatment solution to evaluate the particle removability
and the film removability. These results are shown in Table 5.
TABLE-US-00005 TABLE 5 Particle Film Run Composition removability
removability Evaluation D-4 A A Example 25 Evaluation D-5 A B
Example 26 Evaluation D-12 A A Example 27 Evaluation D-13 A A
Example 28 Evaluation D-14 A A Example 29 Evaluation D-15 A A
Example 30 Evaluation D-16 A A Example 31 Comparative c-3 C C
Evaluation Example 8
Evaluation Examples 32 to 36 and Comparative Evaluation Example
9
[0163] The procedure of Evaluation Examples 20 to 24, and
Comparative Evaluation Example 6 was repeated except that pure
water was used as a stripping treatment solution in place of the
dissolving treatment solution to evaluate the particle removability
and the film removability. These results are shown in Table 6.
TABLE-US-00006 TABLE 6 Wafer material SiN TiN Particle Film
Particle Film Compo- remov- remov- remov- remov- Run sition ability
ability ability ability Evaluation D-12 A A A A Example 32
Evaluation D-13 B B A A Example 33 Evaluation D-14 B B A A Example
34 Evaluation D-15 B B A A Example 35 Evaluation D-16 B B A A
Example 36 Comparative c-3 C C C C Evaluation Example 9
[0164] Further effects and modification examples may be readily
thought out by those skilled in the art. Therefore, a wider
embodiment of the present invention is not limited to certain
detailed and representative exemplary embodiments as shown and
described above. Consequently, various modifications may be
possible without departing from the idea or scope of the overall
concept of the invention that is defined by the attached claims and
the equivalents thereof. [0165] (1) A substrate cleaning method
comprising:
[0166] a film-forming treatment solution supply step of supplying
to a substrate, a film-forming treatment solution comprising an
organic solvent and a fluorine-containing polymer that is soluble
in the organic solvent; and
[0167] a removing solution supply step of supplying to a treatment
film formed by solidification or curing of the film-forming
treatment solution on the substrate, a removing solution capable of
removing the treatment film. [0168] (2) The substrate cleaning
method according to (1), wherein the polymer has a partial
structure represented by the following formula (1):
##STR00007##
[0169] wherein
[0170] R.sup.1 and R.sup.2 each independently represents a hydrogen
atom, a fluorine atom, an alkyl group having 1 to 8 carbon atoms,
or a fluorinated alkyl group having 1 to 8 carbon atoms, provided
that at least one of R.sup.1 and R.sup.2 is a fluorine atom or a
fluorinated alkyl group having 1 to 8 carbon atoms; and
[0171] the symbol * shows a bonding site with another atom
constituting the polymer. [0172] (3) The substrate cleaning method
according to (2), wherein the film-forming treatment solution
further contains a low-molecular organic acid. [0173] (4) The
substrate cleaning method according to claim 3, wherein the
low-molecular organic acid is a polycarboxylic acid. [0174] (5) The
substrate cleaning method according to any one of (2) to (4),
wherein the film-forming treatment solution contains water at an
amount of 20% or less by mass relative to total mass of the organic
solvent and the water. [0175] (6) The substrate cleaning method
according to any one of (1) to (5), wherein the removing solution
supply step comprises:
[0176] a stripping treatment solution supply step of supplying to
the treatment film, a stripping treatment solution capable of
stripping the treatment film from the substrate; and
[0177] a dissolving treatment solution supply step of, after the
stripping treatment solution supply step, supplying to the
treatment film, a dissolving treatment solution capable of
dissolving the treatment film. [0178] (7) The substrate cleaning
method according to (6), wherein the stripping treatment solution
is pure water. [0179] (8) A non-transitory computer-readable
recording medium storing a program that is executable by a computer
and controls a substrate cleaning system, wherein upon execution of
the program, the computer controls the substrate cleaning system so
that the substrate cleaning method according to any one of (1) to
(7) is performed.
EXPLANATION OF REFERENCES
[0179] [0180] W: Wafer [0181] P: Particle [0182] 1: Substrate
cleaning system [0183] 2: Carry-in/out station [0184] 3: Processing
station [0185] 4: Control device [0186] 14: Substrate cleaning
device [0187] 20: Chamber [0188] 21: FFU [0189] 30: Substrate
holding mechanism [0190] 40: Solution supply unit [0191] 45a:
Film-forming treatment solution source [0192] 45b: DIW source
[0193] 45c: Alkaline aqueous solution source [0194] 50: Recovery
cup
* * * * *